Ok, some bad news. The .evt files specified in the descr_skeleton.txt file get parsed into binary and saved into the skeletons.dat file, and so they have not actually been shipped with the game in an extractable form.

But also some good news: the .evt files are essentially text files, with a fairly simple layout, like so:

event SOUND_AMBIENT stretch_back 6 6
event SOUND_AMBIENT neck_crack 20 20

or so:

event SOUND_BANK unit_run 4 6 RANDOM
event SOUND_BANK unit_run 10 12 RANDOM
event SOUND_BANK unit_march 14 18 RANDOM
event SOUND_BANK unit_march 20 24 RANDOM

The valid sound categories for the second word are: SOUND, SOUND_BANK, SHOCKWAVE, SOUND_VOICE, and SOUND_AMBIENT, the third word is a tag for lookup into the category, while the two numbers are frame counts for start and end times (in the anims 20 fps frame counter).

I'll have a chat with the powers that be and see if we can make the original .evt files available.